1. Field of the Invention
The present invention relates to a so-called serial type recording apparatus wherein a head is mounted on a carriage moved relative to a recording medium, character data arranged in a row is printed and recorded on the recording medium along the direction substantially orthogonal to the direction of movement of the carriage and the carriage is moved so as to print and record character data on each strip region.
2. Description of the Related Art
As the serial type recoding apparatus, there have been developed those of types such as a dot-impact type, a thermal-transfer type, an inkjet type, etc. In particular, an inkjet recording apparatus has been noted wherein heat is applied to ink by a heater to produce bubbles and the ink is discharged into a recording medium through delivery holes of a head under pressure produced by expansion of the bubbles to thereby record data on the recording medium.
There is now a demand for a recording apparatus corresponding to DTP (Desk Top Publishing) and the like. Accordingly, this type of recording apparatus has a number of functions in that, for example, kinds, sizes and recording positions of characters to be recorded can be specified accurately. When such various characters are recorded, they are developed in the form of bit map images and then recorded. The serial type recording apparatus has a problem in that since the characters are recorded for each strip region, they overflow one strip region when they are developed in the form of the bit map images. Where a large character extends over a plurality of strip regions and the positioning of its font is made at the corner of the lower part on the left side of the character, the character is often developed in a state of being spread over the previous strip region. When the character overflows one strip region and is developed in a state of being spread over the next strip region, a bit map image corresponding to only a portion developable on a strip region used for recording of the character is stored in a bit map memory corresponding to the strip region. After completion of its recording, a bit map image in the next strip region is newly developed inclusive of a bit map image corresponding to the remaining portion. Then, the developed bit map images can be stored and recorded in the bit map memory. However, when the character is developed in a state of being spread over the previous strip region, the bit map image developed till now is erased at the time that the character extending over the previous strip region is developed. Thereafter, the portion developed in the previous strip region is developed in the bit map memory. After the recording of character data on the strip region, a recording medium is normally fed a predetermined amount. Therefore, the recording medium is conveyed in the reverse direction to record the bit map image corresponding to the portion developed in the previous strip region, thereby recording the character data on the strip region. After completion of its recording, the recording medium is fed a predetermined amount again. Further, the bit map development is made to the recording strip region to thereby record the bit map image.
In the conventional recording apparatus as described above, the bit map image is re-developed when it is desired to record the character or the like extending over the previous strip region. Thus, such re-development causes a problem that a processing time interval is made long and a recording speed is reduced in particular. The feeding of the recording medium in the reverse direction should be done and a reduction in recording speed is produced. Particularly, the inkjet recording apparatus is accompanied by a problem that droplets of ink which are not yet dried, is rubbed due to the feeding of the recording medium in the reverse direction to thereby cause a reduction in quality of an image to be recorded. Further, the accuracy of feeding of the recording medium in the reverse direction is low and an image to be recorded after completion of its feeding is positionally displaced. Thus, a further reduction in quality of the image is produced.
In order to solve such problems, there is proposed an arrangement disclosed in Japanese Patent Application Laid-Open Publication No. 4-133765 wherein recoding data are rearranged in order of recording positions and recorded in their order of rearrangement and the data which overflow a storage region, are temporarily withdrawn or kept away. According to the arrangement, the feeding of the recording medium in the reverse direction can be avoided. However, the rearrangement of the data requires much time. It is also necessary for this type of technique to provide a memory for temporarily storing or keep away the overflowed data. This memory is used only when the data is temporarily stored therein for withdrawal and hence the memory is not effectively used.
Further, there has been developed a recording apparatus wherein the capacity of a memory for temporarily storing data therein is made greater so that a storing process can be made for each page. This type of recording apparatus has drawbacks in that although a required process may not be effected on the boundary between the aforementioned recording regions, a mass-capacity type memory is required, thereby raising the cost of the recording apparatus.
In order to improve a processing speed, there is considered an application of a technique of a so-called alternate buffer which has bit map memories corresponding to a plurality of strip recording regions and alternately reads data from and writes it into the memories. According to the technique, the memories can be effectively utilized. In this type of technique, however, consideration is given only to the case where a developed bit map image falls within a strip region. Therefore, such a technique cannot cope with the case where the bit map image is developed so as to extend over the aforementioned previous strip region.